Detection: Splunk Sensitive Information Disclosure in DEBUG Logging Channels

Updated Date: 2024-10-14 ID: 93dc7182-c5da-4085-82ec-401abf33d623 Author: Rod Soto, Eric McGinnis, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

In Splunk versions 9.3, 9.2, 9.1, 9.1.5 Applications which have been enabled with logging level DEBUG may write sensitive information such as keys, tokens, or other sensitive strings into the internal index.

Search

1`splunkd` log_level="DEBUG" AND component IN ("REST_Calls", "AdminManager", "JSONWebToken")
2
3| stats count min(_time) as firstTime max(_time) as lastTime by host splunk_server log_level component event_message
4
5| `security_content_ctime(firstTime)`
6
7| `security_content_ctime(lastTime)`
8
9| `splunk_sensitive_information_disclosure_in_debug_logging_channels_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Splunk	Splunk	`'splunkd_ui_access'`	`'splunkd_ui_access.log'`	N/A

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
splunk_sensitive_information_disclosure_in_debug_logging_channels_filter	`search *`

splunk_sensitive_information_disclosure_in_debug_logging_channels_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1552	Unsecured Credentials	Credential Access

KillChainPhase.EXPLOITAITON

NistCategory.DE_AE

Cis18Value.CIS_10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Risk Event	False

This configuration file applies to all detections of type hunting.

Implementation

Requires access to _internal index. It is recommended to inventory and modify the search for specific apps that may have DEBUG logging enabled.

Known False Positives

There will be false positives as not every message to the DEBUG log will expose sensitive information, such as keys or other secrets.

Associated Analytic Story

Splunk Vulnerabilities

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Possible sensitive credential information found via DEBUG logging in component $component$ at $host$ _internal index	45	50	90

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`/opt/splunk/var/log/splunk/splunkd.log`	`splunkd`
Integration	✅ Passing	Dataset	`/opt/splunk/var/log/splunk/splunkd.log`	`splunkd`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1